Energy from a turbine is converted into a form suitable for collection of energy from multiple turbines. This is preferably done cost-effectively, safely, and with few system failures. The power conversion chain of a conventional wind turbine typically includes a rotor assembly, a gear box connecting the rotor assembly to an electric generator, and a step-up transformer electrically coupling the electric generator to an AC-to-AC converter. The wind turbine also includes an auxiliary load that implements various wind turbine functions such as control, communication, safety, etc. The auxiliary load may be required to be powered even when the electric generator outputs insufficient power. The wind turbine is typically shut down when the auxiliary load loses power.
Auxiliary power for wind turbines with an AC output is conventionally realized by providing a three-winding transformer at the AC output of the turbine, which is not easily achieved when the turbine output is DC. A turbine with DC output ideally must provide auxiliary power through other means which must have a very high availability and should provide power for various processes including start-up and safe shutdown of the wind turbine.